Process of joining metals



May l, 1923.

C. F. KETTERING PROCESS OF JOINING METALS Filed D60' l5, 1920 2 Sheets-Sheet l C3. F. KETTERiNG PROCESS oF JOINING METALS Filed DGC- 15, 1920 2 Sheets-Sheet 9 May 1, 1923.

Patented May l, 1923.

UNITED STATES CHARLES F. KETTERING, OF DAYTON, OHIO, ASSIGNOR TO GENERAL MOTORS RESEARCH PATENT OFFICE.

CORPORATION, OF DAYTON, OHIO, A CORPORATION F DELAWARE.

PROCESS or JOINING METALS.

Application led December 15, 1920. Serial No. 430,841.

T0 all whom 'it may comer/n.:

Be it known that I, CHARLES F. KETTER- ING, a citizen of the United States of America, residing at Dayton, county of Montgomery, and State of Ohio, have invented certain new and useful improvements in Processes of Joining Metals, of which the following is a full, clear, and exact description.

The present process relates to the joining of metals and in its preferred form, which has been chosen for the purpose of description and illustration, relates more particularly to the attachment of non-ferrous metal cooling elements (such as copper fins) to ferrous metal cylinders for internal-combustion engines.

Among the objects of the invention is the shortening of the time consumed in such 2o operations and the conducting of such operations under more easily and exactly controlled conditions;

Further objects and advantages of the present invention will be apparent from the ,following description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. l represents more or less diagrammatically a form of furnace for carrying out the present process, parts being in longitudinal section.

Fig. 2 is an elevation of an assembly of an engine cylinder and fins ready to be placed in the furnace.

Fig. 3 is a detail of the assembly shown in Fig. 2 but on a greatly enlarged scale. igs. 4 and 5 are diagrammatic representations of modified forms of furnaces suitable for use in the present process.

In Fig. 1 the furnace proper consists of a frame 10 having an upright portion 11 to which is attached by means of suitable a clamrps 12 a water cooled copper coil 13, having leads 14 for both water and electrical energy. The coil is suitably insulated and lagged as indicated at 15.

Within the coil 13 there is a quartz tube m indicated at 2O for the purpose of electrically insulating materials within the furnace and also for protecting the coil to some extent against radiated heat.

Mounted upon the opposite end of the frame 10 from the upright l1 are suitable posts 30 provided with bearings in their upperends for shaft 3l. This shaft 3l carries` at the end opposite the furnace, means for rotation, represented by a pulley 3Q. At its other end, nearest the furnace, the shaft is provided with means for attaching the worlr piece. ln the present illustration, the work piece is represented as being an internalcombustion engine cylinder 35 assembled with fins 36 as illustrated in Fig. 2. This cylinder is bolt-ed to a plate 33 attached to the end Lof shaft 31.

lt will be noted that this supporting and rotating shaft 31 should be so mounted as to permit the insertion and removal of the work piece into and from the furnace tube 20.

The cylinder assembly represented in Fig. 2 consists of the cylinder proper 35, and the cooling element-s 36 which latter are placed around the cylinder with an interposed sheet of brazing brass and suitable fiuxes described in my application, Serial lilo. lell, filed November 9, 1921, upon the process of which the present case may be considered improvement.

ln the former application, the rotation of the assembly while heating is mentioned as one method of maintaining the distribution of the brazing metal and this or an equivalent step is quite important in such operations as attaching copper fins to cylinders in the manner shown, and it is for this same purpose that the rpresent construction is chosen.

The present assembly differs from the assembly described in the previo-us applica tion, however, in that the wires 37, used to hold the assembly together while heating, are insulated from the cooling elements against the passage of both heat and electric current. rThis may be accomplished in several ways and I have indicated on the drawing, the use of a thin strip of insulating material, preferably asbestos, indicated at 33. Further. these wires 37 should be so arranged as to break the circuit formed by twisting the ends and one way of doing this is to twist a piece of insulating material between the ends of the Wires as indicated in Fig, 3. Other materials may be used to accomplish this same result and other materials can undoubtedly be used in the place of asbestos.

The operation of the apparatus just described is as follows.

The assembly of cooling elements and cylinder is tirst bolted or otherwise secured to the supporting and rotating shaft 3l and is then inserted into the tube 20 oil the furnace, care being taken to position the cylinder` at such location in the furnace that the head at) ol the cylinder is located at a point within the influence of the current in coil l5 that the heating of the head and the walls ot the cylinder' will be uniform. No exact information need be given as to the placing ot' the cylinder within the coil as its position will depend upon the dimensions ot the cylinder, that is, upon the thickness ot the walls and head and upon the length of the cylinder. However, this location can be readily and easily determined.

Vif/'hen the cylinderhas been suitably prepared and positioned in the furnace, cooling water is allowed to flow through the coil and a current of high itrequency is also allowed to flow therethrough. The result ot this/flow of current is that any conducting material inside ot the coil has induced therein currents which will cause it to become heated, as is well known in the induction `furnace art. The coil is formed ot a small pipe and the water is allowed to flow therethrough solely for the purpose ot keepingthe metal ot the coil at a sutliciently low temperature to prevent its being burnt through by the intense heat generated.

TWhile the above form of furnace is considered at present. the preferable torm ot apparatus tor carrying out the process, other terms ot induction furnaces can be very readily used 'for the operation.

For example, in Fig. 4, there is shown a diagrammatic representation ot a torni ot furnace more or less similar to that of Fig. l, but in this case, the coil 15 is inserted within the cylinder' 35 and the whole is enclosed Within a suitable casing 50 for the purpose ot heat and electrical insulation.

Still another form is represented diagrammatically in Fig. 5, and this type is the socalled transformer type.

ln Fig. 5, the coil l5n is at one side ot a suitable core 60. and the cylinder which takes the place of the secondary winding. is positioned around another portion ot the same core as indicated at 35a.

In order that the cylinder may be placed in proper' position over this other portion ot the core the latter may be provided with a suitable hinge as indicated at Gl. ln this form also, -the cylinder is preferablyv enclosed in a suitable heat insulating'casing G2 and may also be mounted for rotation as in the other forms.

lVhile there has been described several forms of apparatus in which the present Aprocess may be carried out, it should be understood that the process is not limited to the forms shown but other apparatus may be devised and found more or less satis factory, in fact it is contemplated that not only may the heat be generated in the metals themselves by induced currents, but it may also be generated in the metals as the result. ot' resistance to the passage ot' currents caused to llow by electromotive forces external to the material to be heated which latter forms part ot the circuit.

lVhile the process in this case is analogous to the process described and claimed in the above mentioned prior application, Serial No. 514,014, it will readily appear that it has several advantages over the prior process, l'or example, the electric heating permits more uniform and accurate control of the heat. Further, particularly in the case ot' joining copper fins to iron or steel engine cylinders, the heating from resistance ot induced currents properly arranged apparatus causes aniuch more rapid and higher healing ot the iron or steel than of the copper, which is very desirable in this operalion.v Again, generating heat within the metal ot a work piece itself, it will readily be seen that by only minor changes inf the apparatus, the heating can be carried out in any kind of an atmosphere that may be tound desirable or even in vacuum.

Further, while the process has been described and illustrated, as applied to attaching cooling elements to an internal-combustion engine cylinder, itshould be understood that it is not limited to the production of such articles, but may be utilized in the preparation of many other and quite different articles. For example, it is contemplated that this proce might be used in a great many brazing operations or in other operations wherein dissimilar metals are to be joined.

Also, while the specific process herein described and illustrated, constitutes a preferred torni of embodiment of the present invention, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

lVhat I claim is as follows:

l. The process of joining metals which coniprises placing the metals in proper relative position together with suitable bonding Inaterials and heating the assembly by generation ot heat within the body ot one or more ot the metals.

2. The process of ljoining metals by brazing which comprises assembling the metals with brazing material and suitable fluxes and heating to the brazing tenlperature by gen eration ot' heat within one or more of the metals themselves.

3. The process of attaching metal cooling elements to cylinders for internal-combustion engines, which comprises assembling the cylinder, the cooling elements, andsuitable attaching medium and heating the assembly by generation of heat within one or more of the metals constituting the assembly.

4. A process of attaching non-ferrous cooling elements to ferrous metal cylinders ywhich comprises assembling the said elements and cylinders in proper relation with interposed attaching material and heating the assembly to the proper temperature by generation of heat within one or more of the metals themselves.

5. A process of attaching non-ferrous cool- `ing elements to ferrous metals cylinders which comprises. assembling the said elements and cylinders in proper relation with 'interposed attaching material and heating the assembly to the proper temperature by generation of heat Within one or more of the metals themselves, While rotating, the assembly.

G. The process of attaching proper cooling elements to internal-combustion engine cylinders which comprises assembling the said elements and cylinders in proper relative positionl with brazing material interposed and, while rotating the assembly, heating the assembly to the brazing temperature by generation of heat Within one or more of the meals themselves.

7. The process of attaching copper cooling ns to ferrous metal engine cylinders which comprises assembling the said fins and cyl` `inders in proper relative position with brazing metal interposed and, While rotating the assembly, heating to the brazing temperature by generation of heat within one or more of the metals themselves.

8. The process of attaching copper cooling fins to ferrous metal engine cylinders which coniprises assembling the said inders in proper relative position with brazing metal interposed and, while maintaining the distribution of the brazing material, heating to the brazing temperature by generation of heat Within one, or more of the metals themselves.

9. The process of joining metals which comprises placing the metals in proper relative position together with suitable bonding materials and heating one or more of the metals by electric currents which are ingulcad therein from an alternating magnetic l0. The process of attaching copper cooling ns to ferrous metal engine cylinders which comprises assembling the said fins and cylinders in proper relative position with brazing material interposed and,`While rotating the assembly, heating to the brazing temperature by heating one or more of the metals by electric currents which are indulcd therein from an alternating magnetic fie r.

In testimony whereof I hereto afiix my signature.

CHARLES F. KETTERING. Vitnesses:

LEE H. EMRI'CK, AnviNA C. LEHMAN. 

